This invention relates to surface cleaning apparatus and in particular to such apparatus of the type that utilizes a liquid to clean a carpet or like surface. A typical fluid extraction surface cleaning apparatus has a container for holding a cleaning liquid, such as a diluted detergent, a pump to dispense the liquid onto the surface and a brush or other means to work the liquid on the surface to remove the dirt. A powerful suction device picks up the liquid through a nozzle and deposits it in a recovery tank.
Such devices have only attained limited use because the above described components have been costly to manufacture and have resulted in a large, heavy package. This bulky package has made such devices difficult to set up and operate and messy to empty of spent fluid and clean up after use. Further, they require a chemical defoamant be put in the recovery tank to prevent the suction from rendering the spent cleaning liquid into objectional foam in the liquid recovery tank.
Further, even when chemical defoamants are used in the detergent solutions or in the recovery tank itself, foam buildup in the recovery tank is a problem. Foam buildup prematurely closes the float valve typically used in such devices to prevent water from entering the suction fan.